Understanding and quantifying the interaction of water films and external
radiation on vertical walls is critical for fire suppression model validation. In this
study, evaporation rates and surface temperatures on heated stainless steel (SS)
and corrugated paperboard (CP) vertical panels were measured. External radiant
heat flux was provided by an intermediate scale calorimeter (ICAL). Heat flux
levels ranged between 7 and 46 kW/m2 and were controlled by varying the
distance between the ICAL and the target panel. Water flows ranging between 70
and 1900 ml/min were used in this study. Surface temperatures were measured
by a custom calibrated long-wave infrared (IR) camera. Thermocapillary
instabilities caused water films to quickly break down into individual rivulets
when exposed to external radiation. The maximum surface temperatures on the
SS panels were lower than those measured on CP panels due to more effective
lateral conduction. The results also showed that water flows on SS surfaces are
more effective in extracting heat than similar water flows on CP panels. The
experimental results are expected to help understand multi-phase heat transfer for
surface flows in fire environments, and to provide validation data for developing
numerical models.
Keywords: IR imaging, film flow, rivulets, evaporation, FireFOAM, fire
suppression, thermal radiation, ICAL.